Fuel control system for diesel engines



Nov. 9, 1948. J. H. CLARK y 2,453,196

FUEL CONTROL SYSTEM FOR DIESEL ENGINES /5 Filed Aug. 2, 1946 KV; YW

Je... /f c/@ff Patented Nov. 9, 1948 UNITED STATES PATENT OFFICE FUEL CONTROL SYSTEM Eon DIESEL ENGINES This invention relates to a fuel control system, and more particularly to a fuel control system for Diesel engines.

The problem of feeding fuel oil to a Diesel engine has long been recognized. The fuel is forced under pressure to the high-pressure injector pumps but there has been inadequate control of the-fuel feed. 'It is therefore a major object of this invention to provide an improved fuel control system embodying a pressure system in y which the fuel is metered and in which a greater or lesser amount of fuel is fed as needed.

Another object of this invention is to provide an improved fuel feed system for Diesel engines in which there is included a by-pass valve for bypassing a greater or lesser amount of fuel to vary the fuel pressure and the amount of fuel fed to the injectors.

A further objectof this invention is to provide in a fuel pressure system for Diesel engines, a pressure pump for feeding the fuel to a metering pump which feeds a charge of fuel to each of the injector pumps and in which the size of the charge is controlled by the amount of pressure and in which a by-pass valve is provided to vary the amount of the pressure. A,

Still another object of this invention is to provide a fuel control system for Diesel engines in which a rotary metering pump is provided in association with a distributor cap so that charges of fuel are metered to the cylinderheads as the pump rotates and in which the size of the charges is controlled by an operator through the foot accelerator or equivalent means.

It is also a further object of this invention to provide a fuel pressure system for Diesel engines in which the fuel is forced under pressure into a Figure 2 isv a plan view of the distributor cap;

Figure 3 is an elevational view of part of the fuel pressure system, showing the fuel pressure pump, the by-pass valve, and the control for the by-pass valve; and

Figure 4 is a sectional detail, taken on line 4-4 of Figure 2, and showing the distributor cap.

Referring to the drawing, the tube I conducts fuel from the fuel supply (not shown) to the pressure pump 2 included in housing 3. Thepressure pump 2 may be of any conventional type. Above the pressure pump 2 is located a pressure regulator valve fitting 4, having a by-pass tube 5 for directing by-passed fuel back to the tube I.

The fitting 4 includes a pressure regulator valve 6, including a valve stem 1 and a valve opening 8 communicating with the tube I above the pressure pump 2. The valve stem 'l is slidably mounted in the bushing 9 and has its outer end in contact with the lever I0, pivoted at II, and normally urged to the left, in Figure 3, by a coil spring I 2, having one end bearing against lever I@ and the other end fastened to a boss I3 on a rod i4. The rod It is reciprocated from a conventional foot accelerator, governor, or hand throttle (not shown) to vary the pressure exerted by spring it on lever I0, and thereby vary the pressure on the valve stem 'i and its position relative valve opening d. Thus control of rod i4 'will control the Valve S to vary the amount of fuel, under pressure from pump 2, that will be by-passed through tting 4 and by-pass tube 5. In normal voperation the pressure of the fuel at opening 8 will oppose the pressure of the spring i2 and varying the pressure of spring I2 through rod Il will vary the size of the valve opening 8 and the amount of by-passed fuel. It is evident that the greater the amount of fuel by-passed, i. e., the larger the opening 8, the less fuel pressure there will be in tube I5, communicating with tube I above the valve fitting 4. Thus when rod Il is moved to thev left, valve stem 'I will be moved to the left to decrease the size of the opening 8, less fuel will be by-passed, and the greater will be the fuel pressure in tube I5. Conversely, when rod Il is moved to the right, the size of valve opening 8 will increase and more fuelwill be by-passed and less` fuel pressure will be evident in tube I5.

The fuel from tube I5 passes into a distributor cap I6; bolted at I1 to a mounting I8. As shown hereinafter, in synchronism with the engine.

The disc 20 is provided with a metering pump '22 composed of a cylinder 23, a piston 24, normally urged outwardly by a coil spring 25, and a screw 28 closing olf the cylinder 23. A passageway 21 has one end communicating with cylinder 23 and its other end in thecircular path of the lower ends of passageways I9 so that as the disc 20 is indexed in synchronism with the motor, a charge of fuel under pressure will pass from passageway I9, through passageway 21 and into the cylinder 23. The size of each charge will vary depending on the fuel pressure since the greater the fuel pressure, the greater the pressure on piston 24. vthe more spring 25 will yield and the greater will be the size of the cylinder chamber. As the disc 20 rotates it will receive a charge from each passageway I9.

Now intermediate the passageways I9, the distributor cap I6 is provided with passageways 28, shown in Figure 4. Now as the passageway 21 reaches each passageway 29, the charge of fuel in the cylinder 23 will be forced out of the cylinder by the pressure of spring 25 on piston 24 and Into the passageway 28. Thus charges .are alternately picked up when passageway 21 is in communication with one of the passageways I9 and discharged when passageway 21 is in comway 29.

A4 cllronism with engine speed: and means coli- -trollable from the engine accelerator for varying the fuel pressure in said pipe; said distributing and metering means comprising an indexing disc.

a cylindrical chamber-in said. disc, a pistonsreciprocable in said chamber to vary the size of y tothe Diesel engine cylinder in synchronism with Each passageway 28 is in communication with a tube 29,- each of which leads to a. high-pressure injector pump (not shown) for forcing the charge of fuel into a cylinder head. Thus each cylinder receives a charge of fuel and since thedistributor disc is indexed in synchronism-with the'engine, each cylinder will receive its charge from one of the tubes 29 at the proper moment.

Also when the engine is operating at full load, movement of rod I4 to the left by the driver, or otherwise, will decrease the amount of fuel bypassed, will increase the fuel pressure in passageways I 9, and thereby increase the size of each charge and thus more fuel, as needed, will reach the engine cylinder. Thus there is a regulation of the fuel as needed by controlling the by-pass. and the fuel is metered accurately to each engine cylinder insuring a smoother operating motor, and eliminating motor racing or running out of control when air leaks occur in the fuel lines.

The fuel system of this invention can be used on high speed automotive type engines or on stationary engines. It is evident that there has been provided a simple positive means of metering the fuel to each cylinder as required depending on the speed and load conditions.

The distributor cap illustrated is for a. fourcylinder engine since there are four passageways I 9 and four passageways 29.. However it is within the purview of this invention to utilize a greater or lesser number of passageways depending on the number of cylinders in the engine.

, While a certain specific embodiment of this invention has been shown. it will be understood that various modifications may be made within the spirit of the invention. Therefore'no limitations on the invention are intended other than are imposed by the scope of the appended claims.

What is claimed is:

1. A fuel control system for Diesel engines comprising-a fuel pipe; means for pumping fuel under pressure through said pipe; a distributing and metering means communicating with said pipe for forming charges of4 fuel and feeding said charges to the Diesel engine cylinders in synengine speed, and means controllable from the engine accelerator for varying the fuel pressure in said pipe, said last-mentioned means comprising a T-fitting in said pipe, a by-pass tube connected to said T-iltting for by-'passing fuel from said pipe to decrease the fuel pressure, a valve in said T-tting for controlling the amount of fuel by-passed and the amount of fuel pressure, said distributing andmetering means comprising an indexing disc, a cylindrical chamber in said disc, a piston. reciprocable in said chamber to vary the size of said chamber. a coil spring normally urging said piston outwardly to decrease the size of said chamber, and a passageway leading from said pipe to said chamber whereby when the fuel pressure is varied, the pressure on said piston against said spring will lvary to vary the size of said chamber.

3. A fuel control system for Diesel engines comprising a fuel pipe. means for pumping fuel under pressure throughsaid pipe, a distributing and metering means communicating with said pipe for forming charges of fuel and feeding said charges to the Diesel engine cylinder in synchronism with engine speed, and means controllable .from the engine accelerator for varying the fuel pressure in said pipe, said distributing and metering means comprising an indexing disc mounted for rotation about a vertical axis, a transversely-extending cylindrical chamber in said disc, a piston reciprocable in said chamber to vary the size of said chamber, resilient means normally urging said piston outwardly to decrease the size of said chamber, and a passageway leading from said pipe to said chamber whereby when the fuel pressure is varied, the pressure on said piston against said resilient means will vary to vary the size of said chamber.

JESS H. CLARK.

REFERENCES CITED The following'references are of record in'the file of this patent:

UNITED STATES PATENTS 

